Smoke rises in Egypt's North Sinai along the border with southern Israel, July 1, 2015. Islamic State militants launched a wide-scale coordinated assault on several military checkpoints in Egypt's North Sinai on Wednesday.

One top official said the attack was "unprecedented in the number of terrorists involved and the types of weapons they are using," including rocket-propelled grenades and car bombs.

The fighting was concentrated near the town of Sheikh Zuweid. Egypt's Islamic State affiliate says 15 separate military checkpoints were targeted.

El-Sissi vows crackdown

Earlier this week, Egyptian President Abdel-Fattah el-Sissi vowed to crack down hard on Islamic militants after a roadside bomb killed the government's top prosecutor, Hisham Barakat.

In this picture taken June 30, 2015, and provided by the office of the Egyptian Presidency, Egyptian president Abdel-Fattah el-Sissi (C) speaks at the funeral for Hisham Barakat, surrounded by the latter's family members.

The president spoke at Barakat's funeral Tuesday, pounding his fist on a lectern as he blaming the killing on the outlawed Muslim Brotherhood.

Islamic extremists have increasingly attacked Egyptian security forces on Sinai since. Sissi, who once was the military chief, led the army's overthrow of the Muslim Brotherhood's pro-Islamist President Mohamed Morsi in 2013.

The prosecutor had overseen the cases against thousands of Islamists, who have been jailed and convicted in mass trials as part of a massive crackdown since Morsi was pushed from office.

Sissi did not give details of his planned reforms, saying they would be unveiled in the coming days.